The graph \(G_f\) belongs to a rational function of the form \(f(x)=\frac{ax^2+b}{x^2-c}\), where \(a,b,c\in\mathbb{R}\).
a) Find the domain and the vertical and horizontal asymptotes from the graph.
b) Read the coordinates of the marked points \(A\) and \(B\). Use them and the asymptotes to find \(a\), \(b\), \(c\), and the function \(f\).
c) Find all x- and y-intercepts.

Hints
- Use the vertical asymptotes to determine \(c\).
- Use the horizontal asymptote to determine the leading-coefficient ratio.
- Substitute a marked point to determine the remaining parameter.
- Set the numerator equal to zero for x-intercepts.
Solution
1. The graph has vertical asymptotes at \(x=-1\) and \(x=1\), so the domain is \(\mathbb{R}\setminus\{-1, 1\}\), and \(c=1\).
2. The horizontal asymptote is \(y=2\). Since the ratio of leading coefficients is \(a\), this gives \(a=2\).
3. The marked points are \(A=(0, 8)\) and \(B=(2, 0)\). Substitute \(A\): \(8=\frac{b}{-1}\), so \(b=-8\).
4. Therefore, \(f(x)=\frac{2x^2-8}{x^2-1}\). The point \(B\) confirms the result because \(f(2)=0\).
5. The y-intercept is \((0, 8)\). For x-intercepts, solve \(2x^2-8=0\), giving \(x=\pm 2\). Thus, the x-intercepts are \((-2, 0)\) and \((2, 0)\).
Answer
a) Domain: \(\mathbb{R}\setminus\{-1, 1\}\); vertical asymptotes: \(x=-1\) and \(x=1\); horizontal asymptote: \(y=2\)
b) \(A=(0, 8)\), \(B=(2, 0)\); \(a=2\), \(b=-8\), \(c=1\); \(f(x)=\frac{2x^2-8}{x^2-1}\)
c) X-intercepts: \((-2, 0)\) and \((2, 0)\); y-intercept: \((0, 8)\)